KIRKUK, Iraq – A triple bombing killed 27 people and wounded scores outside a police station Thursday, heightening tensions in a northern Iraqi city already on edge after a string of kidnappings and attacks against security officers.

The new violence adds to strain that already besets Kirkuk, a city that has long been plagued by ethnic squabbles over land and oil fields. Iraqi and U.S. officials long have feared Kirkuk and the disputed lands surrounding it — sandwiched between Arab villages and an autonomous Kurdish region — could destabilize the country if American forces leave at the end of this year on schedule.

“This shows there is no government in this country,” railed Ahmed Salih, 55, sitting next to a hospital bed where his 30-year-old son, Omar Ahmed, lay with bandages around his head and legs. “How such an incident can take place at the police station, where there is security, is nonsense.”

The first blast, a bomb stuck to a car in a parking lot in central Kirkuk, lured policemen out of their fortified headquarters to investigate around 9 a.m., said police Capt. Abdul Salam Zangana. Three minutes later, a second blast rocked the lot when a car packed with explosives blew up in the crowd of police.

“The boots of police officers were scattered at the scene,” said one a police officer, Ahmed Hamid, who survived the strike. “I saw a severed hand on the ground.”

The third bomb, planted on a road leading to a hospital, set cars and trucks ablaze when it exploded about 550 yards (500 meters) away less than an hour later. Zangana said it targeted a police patrol near a mosque.

In all, the blasts killed 27 — most of them police officers — and wounded at least 60 people, said provincial health director Siddiq Omar. Eyewitness Adnan Karim described the scene as “a chaos of terror and fear.”

Located 180 miles (290 kilometers) north of Baghdad, Kirkuk has been an ethnic flashpoint for years among Kurds, Arabs and Turkomen, who each claim the oil-rich city as their own. Kirkuk’s two largest ethnic groups have their own competing security forces — the Arab national police and the predominantly Kurdish peshmerga forces — and that division has stoked tensions.

Within the last 10 days alone, police patrols in Kirkuk have been targeted in five roadside bombings and an Iraqi army base has been hit by two Kaytusha rockets, said city police Col. Sherzad Mofari.

In Mosul, another major city within the disputed territories, four Iraqi army soldiers were killed by a roadside bomb Thursday afternoon, a policeman said.

Also, Kirkuk kidnappers also killed a policeman and a Christian construction worker. The latter was dismembered after his attackers gave up on collecting the $100,000 random they had demanded.

Mofari blamed the violent upsurge on al-Qaida and its allies in Iraq, which seek to stir up Kirkuk’s tensions. “They are trying to keep this instability of security in the city for a long time,” he said.

American military commanders have long worried that the simmering fight over Kirkuk could provoke violence that could spread to the rest of the country. For the last several years, U.S. troops have worked to build partnerships between Iraqi army forces and the Kurdish security forces, known as peshmerga, to secure the swath of disputed lands that stretches over three northern Iraqi provinces — and over some of the world’s most lucrative oil reserves.

But as the U.S. troops withdraw, there is little indication the Kurdish-Arab partnerships will hold, and officials gloomily predict they could return to violence if the Americans leave as scheduled on Dec. 31.

In February, for example, the Kurdish government sent thousands of peshmerga around Kirkuk, claiming to be protecting the city from planned demonstrations that might turn violent. But the incursion scared Arab and Turkomen residents, who called it a thinly veiled attempt to surround Kirkuk with Kurdish forces. The peshmerga pulled back a few weeks later and the crisis passed without bloodshed.

In Baghdad, lawmakers are still haggling over rules for taking a national census that that would determine Kirkuk’s residency — and therefore which ethnic group can rightfully claim power — trying to shape the eligibility requirements to best suit their constituents.

Hours after the bombings, the U.N. envoy to Iraq, Ad Melkert, called on all sides to quickly settle the disputes to prove that Iraqi leaders want to ensure security and stability across the country. The U.N. has been working with Kirkuk’s leaders for years to settle the dispute over the territory and get the census taken, but few believe it will be resolved any time soon.

At one hospital where victims were taken, some said they were close to giving up hope.

“This is because of carelessness of security,” said Awaz Kamal, 45, crying as she watched her son, policeman Saman Salih, being prepared for an operation to remove shrapnel from his stomach.

Around them, bloodied and bandaged victims lay on the floor, because the beds were already filled with patients.

Then a police truck pulled into the hospital driveway with four bodies lying motionless in the truck bed. It was not clear whether they were alive or dead.